井筒内细长抽油杆柱是石油工程中特有结构，考虑旋转抽油杆柱可能在任意井深和井眼圆周方向上与井筒产生的碰撞接触，建立了旋转抽油杆柱动力学模型，并采用动力间隙元和空间梁单元、Newmark法进行仿真。经B3-4-P31等井的应用表明：通过仿真设计的抽油杆柱和扶正器安放位置，能够在井下安全可靠工作，避免了抽油杆柱发生脱断、偏磨事故。该方法已在大庆油田得到应用，也可以在其它油田推广应用。

This paper presents a nonlinear finite element method to resolve the problemof the nonlinear contact between the drillstring and hole wall by using a Multi directional Contact Gap lement(MCGE)contacting at appropriate positions in each beam element.The method was successfully applied to the Daqing Oil Field GP1 well.It was shown that the drillstring's contact resistance at any well depth could be obtained by calculations and that as the error in the calculation of the hole top load is below 10%,the calculation result can provide theoretical basis for the design and operation of drillstrings.